AQA Physics Unit 1 PHYA1 20th May 2013

I think the Astronomical Data along with some of the constants are used in A2
But still, I'm not sure why it's in our booklets...

Why are electrons with different kinetic energies emitted when light with photons of the same energy is shone onto a metal? I can't find it in the book but I remember a question on it. Thanks

Anyone know the circuit symbol for a variable power supply? A lot of the 6 markers want this.
is it this: http://rpmedia.ask.com/ts?u=/wikipedia/commons/thumb/1/1b/Variable_capacitor_symbol.svg/120px-Variable_capacitor_symbol.svg.png

This may seem silly but can anyone give me a definition to learn for emf?

Does anyone know any definite information on significant figures on the physics exams? I know the norm is do it to the same significant figures as to the highest S.F. as what they've given to you in the question, but mark schemes clearly disagree with this.

On the questions where it states "Do it to an appropriate amount of S.F." it's always the same S.F. as what they've given you.

However there is no congruency anywhere else, sometimes they give all their values in 2 S.F. and expect a 3 S.F. answer on the mark scheme. Sometimes they give 3 S.F and expect 2 S.F answer in the mark scheme.

I'm totally confused. Does anyone know whether you lose marks if you give your answer to 3 S.F. in questions where they don't mention "Do it to an appropriate amount of S.F." but the mark scheme gives the correct answer to 2 S.F.?

Why can't they just do it like maths and expect 3 S.F. to most of the questions. /rant over and any help appreciated

Anyone know the circuit symbol for a variable power supply? A lot of the 6 markers want this.
is it this: http://rpmedia.ask.com/ts?u=/wikipedia/commons/thumb/1/1b/Variable_capacitor_symbol.svg/120px-Variable_capacitor_symbol.svg.png

Yeah it's basically that As long as you have the symbol for the source of power, i.e. the cell, and the arrow to represent that it varies, you couldn't really be wrong! If you have to include it in a diagram, there's nothing wrong with labelling it as a variable power supply, if anything it's better!

Because some the electron will be deeper into the metal and require more energy to release them, therefore they will have less Kinetic Energy compared to those that were released from atoms on the surface of the metal for example

With potential dividers, how are we meant to know which resistors are R1 and R2?


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It's the work done per coulomb charge when there's no resistance including internal resistance.

The voltage equals the EMF when current equals zero

V= EMF - Ir

I think that's about all you need to know

Does anyone have a list of all the important formulas we'll need to use?

Also, what do you lot think the 6 marker will be on? I'm predicting something on oscilloscopes to be honest.

The notational doesn't really matter so much but R₂ is typically the with V_out across it... the one you are getting the potential from basically

Unlikely oscilloscopes will come as it came in June 2012, I think it will be so etching about the photoelectric effect as it hasn't come since 2010


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